Siddhartha Raval asked how to take care of a laptop battery so that it lasts a long time.

Batteries don't last forever. Like everything except diamonds and viral tweets, they eventually wear out. But with proper care, a laptop battery can still carry a sufficient charge until you're ready to move on to a better laptop.

But it's a tradeoff. Taking the best care of your laptop battery just may be more of a hassle than it's worth.

The amount of Random Access Memory (RAM) in your PC may or may not be the machine’s major bottleneck. But it will likely speed things up, and it’s easier to install than an SSD, which requires you to move your operating system and other files.

But you have to know not only what kind of RAM your PC can take, but also how much of it.

Frank Hammond asked how to access the AppData folder and copy files from it.

The Application Data—or AppData—folder contains data created by programs. Almost every program you install creates its own folder in AppData and stores information there. At least in theory, users don’t have to worry about these files.

But in reality, you probably do. For instance, my personalized Microsoft Word templates and Sticky Notes file all reside inside AppData. If you’re using an older version of Outlook, that program’s data is probably in AppData, as well.

Peter asked for a way to “remap the Caps Lock key so it does nothing.” He wants to avoid accidentally hitting that key and finding himself typing ALL CAPS.

You can go into the Windows Registry and change how Windows interprets the keyboard code, so that Caps Lock can do something else or nothing at all. That way, you won’t accidentally switch to all-caps.

But even by the standards of Registry editing, it’s a tough hack. So I’m supplying an easier fix.

Mrinal Thakur asked “What should I buy, an external hard drive, an external SSD, or a pen drive?”

My quick answer: Use an external hard drive for backup. Use a flash drive or an SSD if you want to move files from one computer to another and a network isn’t practical.

The long answer: It all depends on how much storage you need, how much you worry about physical damage, and how much you’re willing to spend. Flash-based storage such as external SSDs or flash drives (also known as pen drives or thumb drives) tend to be more robust: Drop one to the ground, and it’s still likely to work. But hard drives provide more storage for the dollar.

Tarek El Nabawe’s PC has 8GB of RAM, but Windows is using only 3.45GB. What happened to the rest?

It sounds as if you’re running a 32-bit version of Windows. A 32-bit operating system has only enough addresses to handle 4GB of memory. Once you get past that, it just doesn’t know what to do with the rest.